Help with states and transitions

RobM

I am trying to figure out how to get this Rectangle to move when clicked back, and forth between these two states. What am I doing incorrectly here? Perhaps I don't need a Bool for this?

import QtQuick 2.12
import QtQuick.Controls 2.5
import QtQuick.Window 2.0

ApplicationWindow
{
  id: root
  visible: true
  width: 640
  height: 480

  Rectangle
  {
    id: theRectangle

    property bool open: true

    height: 75
    width: 150
    anchors.centerIn: parent
    color: "blue"

    states: [
      State
      {
        name: "closedState"
        PropertyChanges
        {
          target: theRectangle
          open: false
        }
      },
      State
      {
        name: "openState"
        PropertyChanges
        {
          target: theRectangle
          open: true
        }
      }
    ]

    transitions: [
      Transition
      {
        from: "openState"
        to: "closedState"

        NumberAnimation
        {
          id: animationClose
          target: theRectangle
          property: "y"
          to: 110
          duration: 1000
        }

      },
      Transition
      {
        from: "closedState"
        to: "openState"

        NumberAnimation
        {
          id: animationOpen
          target: theRectangle
          property: "y"
          to: 0
          duration: 1000
        }
      }
    ]

    MouseArea
    {
      anchors.fill: parent
      onClicked: theRectangle.open ? theRectangle.state = "openState" : theRectangle.state = "closedState"
    }
  }
}

GrecKo

Alternatively you can do it without state, I prefer to avoid state as much as possible, it's too verbose for my linking:

Rectangle {
    id: theRectangle
    height: 75
    width: 150
    y : open ? 0 : 110
    color: open ? "blue" : "red"
    property bool open: true
    
    Behavior on y {
        NumberAnimation {
            easing.type: Easing.InOutQuad
            duration: 1000
        }
    }
    
    MouseArea {
        anchors.fill: parent
        onClicked: theRectangle.open = !theRectangle.open
    }
}

RobM

I have managed to get this working, but I can't seem to get it working using Transitions...

import QtQuick 2.12
import QtQuick.Controls 2.5
import QtQuick.Window 2.0

ApplicationWindow
{
  id: root
  visible: true
  width: 640
  height: 480

  NumberAnimation
  {
    id: animationClose
    target: theRectangle
    property: "y"
    to: 110
    duration: 1000
  }

  NumberAnimation
  {
    id: animationOpen
    target: theRectangle
    property: "y"
    to: 0
    duration: 1000
  }

  Rectangle
  {
    id: theRectangle

    property bool open: true

    onOpenChanged: open ? animationOpen.start() : animationClose.start()

    height: 75
    width: 150
    color: "blue"
    state: "openState"

    states: [
      State
      {
        name: "closedState"
        PropertyChanges
        {
          target: theRectangle
          open: false
        }
      },
      State
      {
        name: "openState"
        PropertyChanges
        {
          target: theRectangle
          open: true
        }
      }
    ]

    MouseArea
    {
      anchors.fill: parent
      onClicked: theRectangle.state === "openState" ? theRectangle.state = "closedState" : theRectangle.state = "openState"
    }
  }
}

Note that I had to bring the NumberAnimation outside of the Rectangle, but I am not sure why.

ODБOï

@RobM hi

there are tons of examples in the docs

RobM

@LeLev said in Help with states and transitions:

@RobM hi

there are tons of examples in the docs

Yeah, I think I just needed to take a better look at them. I had my Transitions doing the work of States, and States doing the work of the Transitions. This is what I came up with. Not sure if you can think of a way to "trim the fat" so to speak. For instance, can you think of a way for this to be done without the Boolean called "open"?

import QtQuick 2.12
import QtQuick.Controls 2.5
import QtQuick.Window 2.0

ApplicationWindow
{
  id: root
  visible: true
  width: 640
  height: 480

  Rectangle
  {
    id: theRectangle

    property bool open: true

    height: 75
    width: 150

    states: [
      State
      {
        name: "closedState"
        when: theRectangle.open === false
        PropertyChanges
        {
          target: theRectangle
          color: "red"
          y: 110
        }
      },
      State
      {
        name: "openState"
        when: theRectangle.open === true
        PropertyChanges
        {
          target: theRectangle
          color: "blue"
          y: 0
        }
      }
    ]

    transitions: Transition 
    {
            NumberAnimation
            {
              properties: "y"
              easing.type: Easing.InOutQuad
              duration: 1000
            }
        }

    MouseArea
    {
      anchors.fill: parent
      onClicked: theRectangle.open = !theRectangle.open
    }
  }
}

ODБOï

@RobM you can do it witout the bool , just change the state directly in the mouse onClicked
but i think it is better to keep it like you did

 Rectangle
    {
        id: theRectangle
        height: 75
        width: 150
        y : 0
        color: "blue"

        states: [
            State
            {
                name: "closedState"
                PropertyChanges
                {
                    target: theRectangle
                    color: "red"
                    y: 110
                }
            },
            State
            {
                name: "openState"

                PropertyChanges
                {
                    target: theRectangle
                    color: "blue"
                    y: 0
                }
            }
        ]

        transitions: Transition
        {
            NumberAnimation
            {
                properties: "y"
                easing.type: Easing.InOutQuad
                duration: 1000
            }
        }

        MouseArea
        {
            anchors.fill: parent
            onClicked:{
                if(theRectangle.state=== "openState")
                    theRectangle.state = "closedState"
                else
                    theRectangle.state = "openState"
            }
        }
    }

GrecKo

Alternatively you can do it without state, I prefer to avoid state as much as possible, it's too verbose for my linking:

Rectangle {
    id: theRectangle
    height: 75
    width: 150
    y : open ? 0 : 110
    color: open ? "blue" : "red"
    property bool open: true
    
    Behavior on y {
        NumberAnimation {
            easing.type: Easing.InOutQuad
            duration: 1000
        }
    }
    
    MouseArea {
        anchors.fill: parent
        onClicked: theRectangle.open = !theRectangle.open
    }
}

RobM

@GrecKo Yes your solution is much more clean than mine, thank you.

ODБOï

hi,
Just as a side note, because the original question and title is about Statesand Transitions :

@RobM said in Help with states and transitions:

much more clean

For such simple case, yes, it is clean. But the more properties changes you have the more your qml file will become messy with bindings everywhere and you still might want to use States

GrecKo

@LeLev said in Help with states and transitions:

But the more properties changes you have the more your qml file will become messy with bindings everywhere and you still might want to use States

That hasn't been my experience, if components are independent enough you rarely change more than 3 properties at a time.
I also don't like the fact that with States you don't directly see in a property binding that it will change, you have to look if there is a State and PropertyChanges somewhere.

That's the way I see it at least, I won't prevent anybody from using State. I just find it cumbersome and seldom use it.